Laminating adhesive

ABSTRACT

[Solution to Problem] The laminating adhesive of the present invention includes a polyisocyanate component (A) and a polyol component (B), wherein the polyisocyanate component (A) contains a polyisocyanate (A1) that does not contain an aromatic ring, and the polyol component (B) contains a macropolyol (B1) that does not contain an aromatic ring but contains a cyclohexane ring.

TECHNICAL FIELD

The present invention relates to a laminating adhesive, and moreparticularly, the present invention relates to a laminating adhesivesuitably used for laminating composite sheets that are used under anoutdoor environment and a similar environment thereof.

BACKGROUND ART

Composite sheets are manufactured by laminating a plurality of sheetmaterials using an adhesive: the sheet materials are selected fromvarious plastic films, metal foils such as aluminum foils, metaldeposited films, silica deposited films, and the like.

For the adhesive used for laminating composite sheets, a twocomponent-type polyurethane adhesive in which a polyisocyanate componentand a polyol component are mixed has been widely used, because of itssuperior adhesion performance.

As such a two component-type polyurethane adhesive, for example, therehas been proposed a two component-curing laminating adhesive compositionin which a polyol component is used as a main component, and apolyisocyanate component is used as a curing agent (for example, seePatent Document 1 below).

The composite sheets are used for outdoor sheets that are used under anoutdoor environment, for example, leisure sheets, tents, plastic greenhouses, sheets for porch, rain coats, umbrellas, hoods, waterproofcloth, sheets for covering automobiles, sheets for covering buildingmaterials, and back sheets for solar batteries.

Patent Document 1: Japanese Unexamined Patent Publication No.2003-129024

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention

However, when the two component-curing laminating adhesive compositiondescribed in the above Patent Document 1 is used for a composite sheetused under an outdoor environment (in the following, referred to as anoutdoor composite sheet), a problem of adhesive yellowing with ageoccurs due to solar ultraviolet radiation, or of delamination is causedfrom adhesive deterioration by rainwater, sunlight irradiation heat, andultraviolet rays.

An object of the present invention is to provide a laminating adhesivethat suppresses the yellowing with age; has excellent durability underrainwater, sunlight irradiation heat, and ultraviolet rays; and evenbrings out excellent adhesion performance.

Means for Solving the Problem

The laminating adhesive of the present invention includes apolyisocyanate component (A) and a polyol component (B), wherein thepolyisocyanate component (A) contains a polyisocyanate (A1)) that doesnot contain an aromatic ring; and the polyol component (B) contains amacropolyol (B1) that does not contain an aromatic ring but contains acyclohexane ring.

Furthermore, in the laminating adhesive of the present invention, it ispreferable that the cyclohexane ring concentration relative to the solidcontent of the polyisocyanate component (A) and the polyol component (B)in total is 2.5 mmol/g or less.

Furthermore, in the laminating adhesive of the present invention, it ispreferable that the macropolyol (B1) is a polyurethane polyol (B1-1′)obtained by reaction of a crystalline polyol (B1-1a′) that does notcontain an aromatic ring and is crystalline at normal temperature with apolyisocyanate (B1-1b) that does not contain an aromatic ring butcontains a cyclohexane ring; it is more preferable that the crystallinepolyol (B1-1a′) contains a crystalline polycarbonate diol that iscrystalline at normal temperature; and it is more preferable that thecrystalline polycarbonate diol that is crystalline at normal temperaturehas a number average molecular weight of 1000 or less.

Furthermore, in the laminating adhesive of the present invention, it ispreferable that the polyisocyanate component (A) does not contain aderivative of isophorone diisocyanate, and in such a case, it ispreferable that the macropolyol (B1) is a polyurethane polyol (B1-1′)obtained by reaction of a crystalline polycarbonate diol that has anumber average molecular weight of 5000 or less, does not contain anaromatic ring, and is crystalline at normal temperature, with apolyisocyanate (B1-1b) that does not contain an aromatic ring butcontains a cyclohexane ring.

Furthermore, the laminating adhesive of the present invention ispreferably used for laminating outdoor composite sheets.

Effects of the Invention

The laminating adhesive of the present invention brings out excellentadhesion performance while suppressing the yellowing with age due tosolar ultraviolet radiation, and suppresses deterioration by rainwater,sunlight irradiation heat, and ultraviolet rays, so that occurrence ofdelamination is prevented. Therefore, the laminating adhesive of thepresent invention is suitable for laminating outdoor composite sheets.

EMBODIMENT OF THE INVENTION

A laminating adhesive of the present invention is a two component-typepolyurethane adhesive, and contains a polyisocyanate component (A) and apolyol component (B).

In the present invention, the polyisocyanate component (A) contains apolyisocyanate (A1) that does not contain an aromatic ring, that is,alicyclic polyisocyanate, aliphatic polyisocyanate, and/or derivativesthereof.

Examples of the alicyclic polyisocyanate include, alicyclic diisocyanatesuch as 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate,1,3-cyclohexane diisocyanate,3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophoronediisocyanate; IPDI), 4,4′-, 2,4′- or 2,2′-dicyclohexylmethanediisocyanate or mixtures thereof (H₁₂MDI), methyl-2,4-cyclohexanediisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3- or1,4-bis(isocyanatomethyl)cyclohexane or mixtures thereof (H₆XDI), andnorbornane diisocyanate (NBDI).

Examples of the aliphatic polyisocyanate include aliphatic diisocyanatesuch as trimethylene diisocyanate, tetramethylene diisocyanate,hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-,2,3- or E3-butylenediisocyanate, and 2,4,4- or2,2,4-trimethylhexamethylene diisocyanate.

Examples of the derivatives of the alicyclic polyisocyanate and thealiphatic polyisocyanate include multimers (dimers, trimers, pentamers,septamers, etc.) of the above-described polyisocyanate (A1) (that is,alicyclic polyisocyanate and/or aliphatic poly isocyanate); abiuret-modified substance of the above-described polyisocyanate (A) (forexample, biuret-modified polyisocyanate produced by reaction of theabove-described polyisocyanate (A1) with water); an allophanate-modifiedsubstance of the polyisocyanate (A1) (for example, allophanate-modifiedpolyisocyanates produced by reaction of the above-describedpolyisocyanate (A1) with monol or polyhydric alcohol (described later));a polyol-modified substance of the polyisocyanate (A1)) (for example,polyol-modified polyisocyanates produced by reaction of thepolyisocyanate (A1)) with polyhydric alcohol (described later)); aurea-modified substance of the polyisocyanate (A1) (for example,urea-modified polyisocyanate produced by reaction of the polyisocyanate(A1) and diamine); oxadiazinetrione (for example, oxadiazinetrionesproduced by reaction of the polyisocyanate (A1)) and carbon dioxide);and a carbodiimide-modified substance of the polyisocyanate (A1)(carbodiimide-modified polyisocyanates produced by decarboxylationcondensation reaction of the polyisocyanate (A1)).

Preferable examples of the polyisocyanate that does not contain anaromatic ring include IPDI, H₁₂MDI, H₆XDI, NBDI, HDI, and derivativesthereof.

In the present invention, the polyol component (B) contains amacropolyol (B1) that does not contain an aromatic ring but contains acyclohexane ring.

Examples of the above-described macropolyol (B1) include a polyurethanepolyol (B1-1) that is obtained by reaction of a polyol (B1-1a) that doesnot contain an aromatic ring with a polyisocyanate (B1-1b) that does notcontain an aromatic ring but contains a cyclohexane ring; and apolyester polyol (described later) that contains alicyclicpolycarboxylic acid (described later) and/or alicyclic diol (describedlater).

Examples of the polyol (B1-1a) that does not contain an aromatic ringinclude a polyester polyol that does not contain an aromatic ring, apolycarbonate polyol that does not contain an aromatic ring, and apolyether polyol that does not contain an aromatic ring.

Preferably, the polyol (B1-1a) that does not contain an aromatic ring isa crystalline polyol (B1-1a′) that does not contain an aromatic ring andis crystalline at normal temperature, such as a crystalline polyesterpolyol that docs not contain an aromatic ring, a crystallinepolycarbonate polyol that does not contain an aromatic ring, and acrystalline polyether polyol that does not contain an aromatic ring.More preferably, the polyol (B1-1a) that does not contain an aromaticring is a crystalline polycarbonate polyol that does not contain anaromatic ring.

The crystalline polyol (B1-1a′) (crystalline polyester polyol,crystalline polycarbonate polyol, and crystalline polyether polyol)refers to a polyol that is not in a liquid state (liquid or fluid) atnormal temperature but in a solid state at normal temperature.

The above-described polyester polyol can be obtained, for example, by acondensation reaction between a polybasic acid selected from aliphaticpolycarboxylic acid and alicyclic polycarboxylic acid, and a polyhydricalcohol selected from aliphatic diol, alicyclic diol, and polyfunctionalpolyol; or by a transesterification reaction between an alkyl ester of apolybasic acid and a polyhydric alcohol.

Examples of the aliphatic polycarboxylic acid include succinic acid,glutaric acid, adipic acid, pimelic acid, cork acid, azelaic acid,sebacic acid, dodecanedioic acid, and hydrogenated dimer acid.

Examples of the alicyclic polycarboxylic acid include hexahydrophthalicacid and tetrahydrophtalic acid.

Examples of the alkyl ester of the polybasic acid include C1-4 alkylesters of the above-described polybasic acids.

Examples of the aliphatic diol include ethylene glycol, diethyleneglycol, triethylene glycol, propylene glycol, dipropylene glycol,tripropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol,2-methyl-1,3-propanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol,2,4-diethyl-1,5-pentanediol, 2,2,4-trimethylpentane-1,3-diol,1,6-hexandiol, neopentyl glycol, 1,5-heptanediol, 1,7-heptanediol,3,3′-dimethylolheptane, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol,1,11-undecanediol, 1,12-undecanediol, 12-hydroxystearyl alcohol, and ahydrogenated dimer diol.

Examples of the alicyclic diol include hydrogenated bisphenol A,hydrogenated xylylenediol, cyclohexanediol, and cyclohexanedimethanol.

Examples of the polyfunctional polyol include an aliphatic polyol havingthree or more hydroxyl groups, such as glycerin, trimethylolpropane,pentaerythritol, and sorbitol.

The condensation reaction or the transesterification reaction can beperformed according to a known process without any particularlimitation, and for example, the respective components are charged, andthe mixture was allowed to react at 150 to 240° C. for 7 to 50 hours.Further, a known catalyst (for example, a titanium-based catalyst, azinc-based catalyst, etc.) can be added for such reactions.

Examples of the above-described polyester polyol include lactone-basedpolyester polyols such as polycaprolactone polyols and polyvalerolactonepolyols obtained by ring-opening polymerization of lactones such asε-caprolactone and γ-valerolactone using the above-described polyhydricalcohol as an initiator.

Examples of the crystalline polyester polyol that does not contain anaromatic ring include polyethylene adipate, polybutylene adipate, andpolyethylene butylene adipate with a number average molecular weight of1000 or more.

The above-described polycarbonate polyol can be obtained, for example,by allowing phosgene, dialkyl carbonate, diallyl carbonate, or alkylenecarbonate to react using the above-described polyhydric alcohol as aninitiator under, for example, presence or absence of a catalyst.

Examples of the crystalline polycarbonate polyol that does not containan aromatic ring include 1,6-hexanediol-base polycarbonate diol with anumber average molecular weight of 400 or more.

The above-described polyether polyol can be obtained, for example, byperforming an addition reaction of alkylene oxides such as ethyleneoxide and/or propylene oxide using the above-described polyhydricalcohol as an initiator. To be specific, examples thereof includepolyethylene glycol, polypropylene glycol, and polyethylenepolypropyleneglycol (random or block copolymer). Further, polytetramethylene glycolobtained by ring-opening polymerization of tetrahydrofurans is anotherexample.

Examples of the crystalline polyether polyol that does not contain anaromatic ring include polyethylene glycol, polyethylenepolypropyleneglycol (ethylene oxide-propylene oxide block copolymer), andpolyoxytetramethylene ether glycol with a number average molecularweight of 1000 or more.

The number average molecular weight of the above-described polyol(B1-1a) (the above-described polyester polyol, polycarbonate polyol, andpolyether polyol) is, for example, 100 to 5000.

In the case when a derivative of3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate is contained asthe polyisocyanate component (A) and when the polyurethane polyol(B1-1′) is prepared using the crystalline polycarbonate diol that is ina crystalline state at normal temperature as the above-describedcrystalline polyol (B1-1a′) in the polyol component (B), the numberaverage molecular weight of the crystalline polycarbonate diol ispreferably 1000 or less. With the crystalline polycarbonate diol havingthe number average molecular weight of 1000 or less, excellenttransparency can be ensured even if the derivative of3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate is contained asthe polyisocyanate component (A). There may be a case where excellenttransparency cannot be ensured when the number average molecular weightof the crystalline polycarbonate diol exceeds 1000 and the derivative of3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate is contained asthe polyisocyanate component (A).

On the other hand, when the polyisocyanate component (A) does notcontain the derivative of3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate and thepolyurethane polyol (B1-1′) is prepared using the crystallinepolycarbonate diol that is in a crystalline state at normal temperatureas the above-described crystalline polyol (B1-1a′) in the polyolcomponent (B), the number average molecular weight of the crystallinepolycarbonate diol is preferably 5000 or less. When the derivative of3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate is not containedas the polyisocyanate component (A) and the number average molecularweight of the crystalline polycarbonate diol is 5000 or less, excellenttransparency can be ensured.

Transparency is an important property particularly for a laminatingadhesive that is used for transparent outdoor composite sheets.

The number average molecular weight in the polyol component (B) can becalculated by a known hydroxyl value measurement method such asacetylation method or phthalic anhydride method and the number of thefunctional group in the initiator or the raw material.

As the above-described polyol (B1-1a), the above-described polyhydricalcohol can also be used in combination with the above-describedpolyester polyol, polycarbonate polyol, and/or polyether polyol. Forsuch a polyhydric alcohol, preferably, the above-described alicyclicdiol can also be used. When the polyhydric alcohol is used together asthe above-described polyol (B1-1a), the polyhydric alcohol is used in anamount of, for example, 0.1 to 50 parts by weight, or preferably 0.5 to30 parts by weight relative to 100 parts by weight of theabove-described polyester polyol, polycarbonate polyol, and/or polyetherpolyol.

Examples of the polyisocyanate (B1-1b) that does not contain an aromaticring but contains a cyclohexane ring include the above-describedalicyclic polyisocyanate and derivatives thereof. Preferable examplesare IPDI, H₁₂MDI, H₆XDI, NBDI, and derivatives thereof.

The polyurethane polyol (B1-1) can be obtained by subjecting theabove-described polyol (B1-1a) and the above-described polyisocyanate(B1-1b) to urethane reaction at such a ratio that the equivalent ratio(NCO/OH) of the isocyanate group in the above-described polyisocyanate(B1-1b) relative to the hydroxyl group in the above-described polyol(B1-1a) is smaller than 1, or preferably 0.5 to 0.9. A known method maybe used for the urethane reaction.

Preferably, the polyurethane polyol (B1-1) is polyurethanepolycarbonatepolyol obtained by reaction of the above-described polycarbonate polyolwith the above-described alicyclic polyisocyanate. More preferably, thepolyurethane polyol (B1-1) is polyurethane crystalline polycarbonatediol obtained by reaction of the above-described crystallinepolycarbonate diol with alicyclic polyisocyanate.

Also, as described above, examples of the macropolyol (B1) include apolyester polyol that contains alicyclic polycarboxylic acid and/oralicyclic diol.

The hydroxyl group equivalent (OH equivalent) of the above-describedmacropolyol (B1) is, for example, 1000 to 15000, or preferably 1500 to10000.

Other than the above-described macropolyol (B1), for example, theabove-described polyhydric alcohol may also be contained in the polyolcomponent (B). When the polyhydric alcohol is contained as the polyolcomponent, for example, 0.01 to 50 parts by weight, or preferably 0.1 to30 parts by weight of the polyhydric alcohol relative to 100 parts byweight of the macropolyol (B1) is contained.

A silane coupling agent may be mixed as necessary in one of or both ofthe polyisocyanate component (A) and the polyol component (B).

The silane coupling agent that may be used is represented, for example,by the structural formula: R—Si≡(X)₃ or R—Si≡(R′)(X)₂ (wherein Rrepresents an organic group having a vinyl, epoxy, amino, imino,isocyanate, or mercapto group; R′ represents a lower alkyl group; and Xrepresents a methoxy group, an ethoxy group, or chlorine atom).

Specific examples of the silane coupling agent include chlorosilanessuch as vinyl trichlorosilane; aminosilanes such asN-β-(aminoethyl)-γ-aminopropyltrimethoxysilane,γ-aminopropyltriethoxysilane,N-β-(aminoethyl)-γ-propylmethyldimethoxysilane,n-(dimethoxymethylsilylpropyl)ethylenediamine,n-(triethoxysilylpropyl)ethylenediamine, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such asγ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,β-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, anddi(γ-glycidoxypropyl)dimethoxysilane; vinyl silanes such asvinyltriethoxysilane; and isocyanate silanes such as3-isocyanatopropyltrimethoxysilane, and3-isocyanatopropyltriethoxysilane.

These silane coupling agents can be used alone or in combination of twoor more. The amount of the silane coupling agent to be blended is, forexample, 0.001 to 10 parts by weight, or preferably 0.01 to 6 parts byweight per 100 parts by weight of the total amount of the polyisocyanatecomponent (A) and the polyol component (B).

Further, additives such as epoxy resins, catalysts, coating improvingagents, leveling agents, antifoaming agents, stabilizers includingantioxidant and ultraviolet absorbers, plasticizers, surfactants,pigments, fillers, organic or inorganic fine particles, and antifungalagents may be blended with either or both of the polyisocyanatecomponent (A) and the polyol component (B) as required. The amount ofthese additives to be blended is appropriately determined according tothe purposes and applications.

When an epoxy resin is to be blended in order to improve adherence, ahydrogenated bisphenol A epoxy resin may be blended to further improveresistance to yellowing.

A laminating adhesive of the present invention is used as a twocomponent-type polyurethane adhesive in which the polyisocyanatecomponent (A) and the polyol component (B) are blended. That is, in thelaminating adhesive of the present invention, the polyisocyanatecomponent (A) and the polyol component (B) are prepared separately inadvance, and the polyisocyanate component (A) and the polyol component(B) are blended upon use, and applied on an adherend (sheet material).The polyisocyanate component (A) and the polyol component (B) areblended at such a ratio that the equivalent ratio (NCO/OH) of theisocyanate group in the polyisocyanate component (A) relative to thehydroxyl group in the polyol component (B) is, for example, 0.6 to 10,or preferably 0.8 to 6.

In the laminating adhesive of the present invention, the concentrationof the cyclohexane ring is, for example, 2.5 mmol/g or less, orpreferably, 2 mmol/g or less, or normally, 0.1 mmol/g or more relativeto the total solid content of the polyisocyanate component (A) and thepolyol component (B). When the concentration of the cyclohexane ringexceeds 2.5 mmol/g, there may be a case where excellent transparency asa laminating adhesive cannot be ensured.

The laminating adhesive of the present invention is, to be specific,prepared as a solvent-based or solventless type, and mainly used forlaminating composite sheets.

For example, when the laminating adhesive is prepared as a solvent-basedtype, the polyisocyanate component (A) and the polyol component (B) arediluted with an organic solvent and blended, and the mixture is appliedon one surface of the sheet material using a solvent-type laminator.Then, after the solvent is evaporated, the sheet is bonded to anothersheet material, and then aged to be cured at normal temperature or underheat. The amount of the mixture applied is set in the range of, forexample, about 2.0 to 10.0 g/m² after evaporation of the solvent.

When the blending viscosity of the polyisocyanate component (A) and thepolyol component (B) is about 100 to 10000 mPa·s, or preferably about100 to 5000 mPa·s at normal temperature to 100° C., the laminatingadhesive can be prepared as a solventless type.

For example, when the laminating adhesive is prepared as a solventlesstype, the polyisocyanate component (A) and the polyol component (B) areblended as is, and the mixture is applied on one surface of the sheetmaterial using a solventless-type laminator. Then, the sheet is bondedto another sheet material, and then aged to be cured at normaltemperature or under heat. The amount of the mixture applied is set inthe range of, for example, about 0.5 to 5.0 g/m².

The sheet material is not limited as long as the sheet can be laminatedas a composite sheet, and examples thereof include metal foils andplastic sheets.

Examples of the metal that may be used to form the metal foil includealuminum, stainless steel, iron, copper, and lead. The thickness of themetal foil is usually 5 to 100 μm, or preferably 7 to 50 μm.

Examples of the plastic that may be used to form the plastic sheetinclude an olefinic polymer (for example, polyethylene andpolypropylene); a polyester polymer (for example, polyalkyleneterephthalate such as polyethylene terephthalate (PET) and polybutyleneterephthalate; polyalkylene naphthalate; and a copolyester that containsthese polyalkylene arylate units as main components); a polyamidepolymer (for example, nylon 6 and nylon 66); and a vinyl polymer (forexample, polyvinyl chloride, ethylene-vinyl acetate copolymer, andethylene-vinyl alcohol copolymer).

The plastic sheet may also include an inorganic layer formed on at leastone side thereof. The inorganic layer may be formed by a vacuumevaporation, sputtering, or sol-gel technique. Examples of the inorganicsubstance that may be used to form the inorganic layer include anelement such as titanium, aluminum, and silicon; or an inorganiccompound including these element(s) (for example, oxide). Specificexamples thereof include an aluminum-deposited sheet and asilica-deposited sheet.

The thickness of the plastic sheet is usually 5 to 200 μm, or preferably10 to 150 μm.

The surfaces of the metal foil and the plastic sheet may be subjected tosurface treatment, such as corona discharge treatment and primertreatment. Further, the metal foil and the plastic sheet may beappropriately printed.

The laminating adhesive of the present invention does not contain anaromatic ring, and therefore yellowing with age can be suppressed.Meanwhile, the laminating adhesive of the present invention contains acyclohexane ring, and therefore excellent adhesive strength andmechanical strength can be ensured over a long period of time. Then, thelaminating adhesive of the present invention can ensure excellentadhesion performance and transparency.

Therefore, the laminating adhesive of the present invention can suppressyellowing with age; has excellent durability under rainwater, sunlightirradiation heat, and ultraviolet rays; and even brings out excellentadhesion performance, so that occurrence of delamination can beprevented. Therefore, the laminating adhesive of the present inventionis suitably used for laminating, in particular, composite sheets usedunder an outdoor environment, i.e., outdoor composite sheets.

To be more specific, the laminating adhesive of the present invention issuitably used for laminating outdoor composite sheets that are usedunder an outdoor environment, such as leisure sheets, tents, plasticgreen houses, sheets for porch, rain coats, umbrellas, hoods, waterproofcloth, sheets for covering automobiles, sheets for covering buildingmaterials, and back sheets for solar batteries.

EXAMPLES

Hereinafter, the present invention will be described in more detail byway of Examples and Comparative Examples, but the present invention isnot limited thereto.

Preparation Example 1 Preparation of Polyol Component A

130.5 g of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate and345.3 g of 1,6-hexanediol-base polycarbonate diol (manufactured by UbeIndustries, Ltd. solid at normal temperature) having a number averagemolecular weight of 500 were stirred under a nitrogen gas stream at 90to 95° C. and the mixture was subjected to urethane reaction, tosynthesize a polyurethane polyol. After confirming that no NCO peak wasfound by IR measurement, 500 g of ethyl acetate and 23.8 g ofγ-glycidoxypropyltrimethoxysilane (KBM403 manufactured by Shin-EtsuChemical Co., Ltd.) were added thereto, thereby obtaining a polyolcomponent A having, a solid content of 50 wt %.

Preparation Example 2 Preparation of Polyol Components B to M

Polyol components B to M were prepared in the same manner as the methodin Preparation Example 1, except that the components and the mixingratios as shown in Table 1 were used.

Preparation Example 3 Preparation of Polyol Component N

330.68 g of isophthalic acid, 71.38 g of ethylene glycol, and 359.31 gof neopentyl glycol were subjected to esterification reaction at 180 to220° C. under a nitrogen gas stream. After a predetermined amount ofwater was distilled off, 402.57 g of sebacic acid was added thereto, andthe resulting mixture was subjected to esterification reaction at 180 to220° C., to give a polyester polyol PE1 having a number averagemolecular weight of about 2,500.

Then, 446.6 g of the polyester polyol PE1, 32.5 g of3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate, 191.4 g of ethylacetate were stirred under a nitrogen gas stream at 90 to 95° C. and themixture was subjected to urethane reaction, to synthesize a polyurethanepolyol.

After confirming that no NCO peak was found by IR measurement, 314.04 gof ethyl acetate, 2.15 g of diethylene glycol, and 23.95 g ofγ-glycidoxypropyltrimetoxysilane (KBM403 manufactured by Shin-EtsuChemical Co., Ltd.) were added thereto, thereby obtaining a polyolcomponent N having a solid content of 50 wt %.

Preparation Example 4 Preparation of Polyol Component O

735.19 g of adipic acid, 184.56 g of ethylene glycol, 83.02 g ofneopentyl glycol, 200.79 g of 1,6-hexanediol were subjected toesterification reaction under a nitrogen gas stream at 180 to 220° C.,to give a polyester polyol PE2 having a number average molecular weightof about 5,500.

Then, 448 g of the polyester polyol PE2, 470.5 g of ethyl acetate, 22.4g of γ-glycidoxypropyltrimetoxysilane (KBM403 manufactured by Shin-EtsuChemical Co., Ltd.) were stirred at 50° C. until the mixture becamehomogenous, to give a polyol component O.

Preparation Example 5 Preparation of Polyol Component P

468 g of 1,6-hexanediol-base polycarbonate diol (manufactured by UbeIndustries, Ltd., solid at normal temperature) having a number averagemolecular weight of 3000, 491.5 g of ethyl acetate, 23.4 g ofγ-glycidoxypropyltrimethoxysilane (KBM403 manufactured by Shin-EtsuChemical Co., Ltd.) were stirred at 50° C. until the mixture becamehomogenous, to give a polyol component P.

Preparation Example 6 Preparation of Polyol Component Q

136.3 g of 1,6-hexanediol, 92.4 g of neopentyl glycol, 95.6 g ofethylene glycol, 292.6 g of isophthalic acid, and 0.2 g of zinc acetatewere subjected to esterification reaction at 180 to 220° C. under anitrogen gas stream. After a predetermined amount of water was distilledoff, 85.8 g of adipic acid was added thereto, and the resulting mixturewas subjected to esterification reaction at 180 to 220° C., to give apolyester polyol PE3 having a number average molecular weight of about10,000.

Then, 381.9 g of ethyl acetate, 45.3 g of a solution of bisphenol Aepoxy resin in ethyl acetate (YD-902LEA60 manufactured by Tohto KaseiCo., Ltd.), 31.3 g of γ-glycidoxypropyltrimetoxysilane (KBM403manufactured by Shin-Etsu Chemical Co., Ltd.), and 1.1 g of phosphoricacid were added thereto and stirred until the mixture became homogenous,to give a polyol component Q.

Preparation Example 7 Preparation of Polyisocyanate Component A

TAKENATE A-3070 (manufactured by Mitsui Chemicals Polyurethanes, Inc., aderivative of hexamethylene diisocyanate, ethyl acetate solution, asolid content of 75 wt %) was prepared as a polyisocyanate component A.

Preparation Example 8 Preparation of Polyisocyanate Component B

124.38 g of Vestanat T 1890/100 (manufactured by Huls AG. a derivativeof 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate) and 0.62 g ofdibutyltin dilaurate were dissolved in 375 g of ethyl acetate, toprepare a polyisocyanate component B as a solution having a solidcontent of 25 wt %.

Preparation Example 9 Preparation of Polyisocyanate Component C

TAKENATE D-120N (manufactured by Mitsui Chemicals Polyurethanes, Inc., aderivative of 1,3-, and 1,4-bis(isocyanatomethyl)cyclohexane, ethylacetate solution, a solid content of 75 wt %) was prepared as apolyisocyanate component C.

TABLE 1 Polyol Component A B C D E F G H I Poly- Polyiso- IPDI 130.575.1 36.4 23.4 113.7 46.7 urethane cyanate H₆XDI 103.3 138.4 PolyolH₁₂MDI 86.2 Polyol PCD-1 345.3 133.0 PCD-2 422.3 341.1 304.0 410.7 140.0114.0 PCD-3 437.0 280.0 PCD-4 451.5 CHDM 43.0 65.8 82.2 PTG2000 PTG3000C2090 PE1 Polyester Polyol Diethylene Glycol KBM403 (parts/100 parts by5 5 5 5 5 5 5 5 5 weight solid content) Solid Content (% by weight) 5050 50 50 50 50 50 50 50 OH Equivalent 2412 3093 4551 5524 2044 1090 31773501 1034 (g/mol (solid content)) Cyclohexane Ring Concentration 1.1740.647 0.330 0.211 1.548 1.988 0.630 0.428 2.61 (mmol/g(solid content))Benzene Ring Concentration 0 0 0 0 0 0 0 0 0 (mmol/g(solid content))Viscosity (mPa · S/25° C.) 280 420 1790 1320 1160 200 1070 640 — PolyolComponent J K L M N O P Q Poly- Polyiso- IPDI 34.0 45.3 32.5 urethanecyanate H₆XD1 23.4 40.0 Polyol H₁₂MDI Polyol PCD-1 PCD-2 PCD-3 218.5PCD-4 468.0 CHDM PTG2000 218.5 PTG3000 451.5 C2090 452.9 457.6 PE1 446.6Polyester Polyol PE2 PE3 Diethylene Glycol 2.15 KBM403 (parts/100 partsby 5 5 5 5 5 5 5 weight solid content) Solid Content (% by weight) 50 5050 50 50 50 50 60 OH Equivalent 5524 3773 11553 11421 6200 2950 15754600 (g/mol (solid content)) Cyclohexane Ring Concentration 0.211 0.3090.389 0.394 0.289 0 0 0 (mmol/g(solid content)) Benzene RingConcentration 0 0 0 0 1.76 0 0 3.04 (mmol/g(solid content)) Viscosity(mPa · S/25° C.) 1980 670 2430 2260 1500 76 92 500

Abbreviations in Table 1 are described in the following.

PCD-1: manufactured by Ube Industries, Ltd., 1,6-hexanediol-basepolycarbonate diol, number average molecular weight of 500, solid atnormal temperaturePCD-2: manufactured by Ube Industries, Ltd., 1,6-hexanediol-basepolycarbonate diol, number average molecular weight of 1000, solid atnormal temperaturePCD-3: manufactured by Ube Industries, Ltd., 1,6-hexanediol-basepolycarbonate diol, number average molecular weight of 2000, solid atnormal temperaturePCD-4: manufactured by Ube Industries, Ltd., 1,6-hexanediol-basepolycarbonate diol, number average molecular weight of 3000, solid atnormal temperatureCHDM: cyclohexanedimethanolPTG2000: manufactured by Hodogaya Chemical Co., LTD.,polytetramethyleneglycol, number average molecular weight of 2000, solidat normal temperaturePTG3000: manufactured by Hodogaya Chemical Co., LTD.,polytetramethyleneglycol, number average molecular weight of 3000, solidat normal temperatureC-2090: manufactured by Kuraray Co., Ltd., polycarbonate diol, numberaverage molecular weight of 2000, liquid at normal temperature

EXAMPLES AND COMPARATIVE EXAMPLES

Laminating adhesives were prepared by blending a polyol component and apolyisocyanate component according to the formulation and ratio shown inTable 2.

Table 2 also shows the cyclohexane ring concentration (mmol/g) relativeto the total (solid content) of the polyol component and thepolyisocyanate component.

Evaluation 1) Peel Test at 80° C.

The laminating adhesives of Examples and Comparative Examples wereapplied in an amount of about 5 g/m² on a treatment surface of a PETsheet (P-60 manufactured by Toray Advanced Film Co Ltd., 16 microns),and after the solvent was evaporated, the PET sheet was bonded to atreatment surface of a CPP sheet (Torayfan No. ZK-99 manufactured byToray Advanced Film Co., Ltd., 60 microns), and then aged for four daysat 60° C., to give a composite sheet. The composite sheet was subjectedto a peel test (201B type (with a constant temperature bath) precisionuniversal testing machine of INTESCO Co., Ltd. a testing sample width 15mm, a testing speed 50 mm/min) at 80° C. to determine the peel strength.The results are shown in Table 2.

In Table 2, under the “mode” in parenthesis, “cohesion” indicatescohesion and peeling of the adhesive itself, suggesting that cohesivestrength of the adhesive is weaker than the adhesion strength at theinterface between the adhesive and the sheet. The “cohesion” indicatesinsufficient adhesion strength even if the peel strength is high.

2) Transparency and Degree of Yellowing

The laminating adhesives of Examples and Comparative Examples wereapplied in an amount of about 5 g/m² on the surface of a glass plate(JIS R 3202 manufactured by Nippon Testpanel Co., Ltd.), and the platewas bonded to an untreated surface of a CPP sheet (NO ZK-99 manufacturedby Toray Advanced Film Co., Ltd 60 microns), and then aged for four daysat 60° C.

Thereafter, the CPP film was peeled off, and irradiated with light usinga QUV device for 50 hours continuously. After the plate was taken fromthe device, transparency was observed, and evaluated as transparencyafter 50 hours. At the same time, a b-value was measured using acolorimeter. Further, light irradiation was performed using the QUVdevice for 100 hours continuously. After the plate was taken from thedevice, transparency was observed, and evaluated as transparency after100 hours. At the same time, a b-value was measured using a colorimeter.Using the difference of these b-values, i.e. Ab-value, the degree ofyellowing of the cured laminating adhesive was evaluated. The resultsare shown in Table 2. QUV device: Dewpanel Light Control Weather MeterFDP (manufactured by Suga Test Instruments Co., Ltd.), continuousirradiation, 70° C., 10% RH, irradiance setting 28 W/m² Colorimeter:spectroscopic colorimeter SE-2000 (manufactured by Nippon DenshokuIndustries Co., Ltd.), measurement method: transmittance method

TABLE 2 Examples Mixing Ratio Cvclohexane and Polyiso- (Weight Ratio)Ring Peel Strength Transparency Degree of Comparative Polyol cyanate OHNCO Concentration at 80° C. (N) After After Yellowing Examples ComponentComponent Component Component (mmol/g) (Mode) 50 Hours 100 HoursΔB-Value Example 1 A A 16 1 1.073 2.6 a a 0.05 (Interface) Example 2 B A16 1 0.591 2.1 a a −0.06 (Interface) Example 3 B B 9 2 1.032 2.2 a a0.08 (Interface) Example 4 C A 20 1 0.307 2.3 a a 0.04 (Interface)Example 5 D A 20 1 0.196 2.3 a a 0.05 (Interface) Example 6 E A 13 11.388 2.5 a a 0.04 (Interface) Example 7 F A 13 2 1.615 1.6 a a 0.08(Interface) Example 8 F B 9 5 2.534 Sheet b b 0.03 Fracture Example 9 FC 4 1 2.587 3.1 a a −0.02 (Surface Layer) Example 10 G A 16 1 0.576 1.7a a 0.06 (Interface) Example 11 H A 16 1 0.391 2.1 a a 0.09 (Interface)Example 12 I A 6 1 2.088 2.1 a a 0.17 (Interface) Example 13 J A 20 10.196 1.0 a a 0.06 (Interface) Example 14 K A 17 1 0.284 4.8 a a −0.07(Surface Layer) Example 15 L A 16 1 0.356 1.2 a a 0.04 (Interface)Example 16 M A 16 1 0.360 1.2 a a 0.06 (Interface) Example 17 A C 16 11.432 2.8 a a 0.04 (Interface) Comp. N A 20 1 0 4.7 c c — * 1 Ex. 1(Interface) Comp. O A 15 1 0 3.4 a a 0.02 Ex. 2 (Cohesion) Comp. P A 9 10 1.2 c c — * 1 Ex. 3 (Interface) Comp. Q A 20 1 0 4.6 a a 2.08 Ex. 4(Cohesion) Transparency Evaluation * 1 Adhesive coating was nottransparent and not able to be evaluated a: Transparent b: Frost c:Opaque

3) Heat-And-Humidity Resistance Test

The laminating adhesives of Examples 1, 2, and 17, and ComparativeExample 4 were applied in an amount of about 5 g/m² on a treatmentsurface of a CPP sheet (NO ZK-99, manufactured by Toray Advanced FilmCo., Ltd., 60 microns), and after the solvent was evaporated, the sheetwas bonded to a treatment surface of another CPP sheet, and then agedfor four days at 60° C. to give a composite sheet. The composite sheetwas set in a Highly Accelerated Stress Test System (model number:TPC-411, manufactured by TABAI ESPEC Corp.), and tested for 168 hoursunder conditions of 120° C., 85% RH, and 1.6 atmospheric pressures.Thereafter, a peel test (201B type precision universal testing machineof INTESCO Co. Ltd., testing sample width 15 mm, testing speed 300mm/min) was performed at room temperature to obtain a peel strength, andthen a retention rate (heat-and-humidity resistance test/peel strengthretention rate (%)) of peel strength after the test of 168 hours wasobtained, setting the peel strength before the test as 100%. The resultsare shown in Table 3.

TABLE 3 Mixing Ratio Cyclohexane Heat-and-Humidity Resistance Polyiso-(Weight Ratio) Ring Test/Peel Strength Examples And Polyol cyanate OHNCO Concentration Retention Rate (%) Comp. Examples Component Componentcomponent component (mmol/g) 168 hr Example 1 A A 16 1 1.073 84 Example2 B A 16 1 0.591 102 Example 17 A C 16 1 1.432 74 Comp. Example 4 Q A 201 0 43

While the illustrative embodiments of the present invention are providedin the above description, such is for illustrative purpose only and itis not to be construed as limiting the scope of the present invention.Modification and variation of the present invention that will be obviousto those skilled in the art is to be covered by the following claims.

INDUSTRIAL APPLICABILITY

The laminating adhesive of the present invention is suitably used forlaminating outdoor composite sheets.

1. A laminating adhesive comprising: a polyisocyanate component (A) anda polyol component (B), wherein the polyisocyanate component (A)contains a polyisocyanate (A1)) that does not contain an aromatic ring,and the polyol component (B) contains a macropolyol (B1) that does notcontain an aromatic ring but contains a cyclohexane ring.
 2. Thelaminating adhesive according to claim 1, wherein the cyclohexane ringconcentration relative to the solid content of the polyisocyanatecomponent (A) and the polyol component (B) in total is 2.5 mmol/g orless.
 3. The laminating adhesive according to claim 1, wherein themacropolyol (B1) is a polyurethane polyol (B1-1′) obtained by reactionof a crystalline polyol (B1-1a′) that does not contain an aromatic ringand is crystalline at normal temperature with a polyisocyanate (B1-1b)that does not contain an aromatic ring but contains a cyclohexane ring.4. The laminating adhesive according to claim 3, wherein the crystallinepolyol (B1-1a′) contains a crystalline polycarbonate diol that iscrystalline at normal temperature.
 5. The laminating adhesive accordingto claim 4, wherein the crystalline polycarbonate diol that iscrystalline at normal temperature has a number average molecular weightof 1000 or less.
 6. The laminating adhesive according to claim 1,wherein the polyisocyanate component (A) does not contain a derivativeof isophorone diisocyanate.
 7. The laminating adhesive according toclaim 6, wherein the macropolyol (B1) is a polyurethane polyol (B1-1′)obtained by reaction of a polycarbonate diol that has a number averagemolecular weight of 5000 or less, does not contain an aromatic ring, andis crystalline at normal temperature, with a polyisocyanate (B1-1b) thatdoes not contain an aromatic ring but contains a cyclohexane ring. 8.The laminating adhesive according to claim 1, wherein the laminatingadhesive is used for laminating outdoor composite sheets.